Wife came home with a peculiar problem with her 2003 S. Indicated she had heat on in the car and yet it was blowing cold (and she could smell a sweet smell, which I assume is coolant of course). The car was overheating. She immediately turned off the heat and cars temperature came back to normal. It was like 15 degrees out, good thing we have heated seats! She drove home with heat off and all was temps were normal. I am thinking a blocked heater core? If she turns off heat, system bypasses the core and circulates as normal correct? Sounds like a fair theory. I've done a search and have not seen this one yet.
THANKS in advance!
Mike P

 

If she smelled antifreeze, feel thru center console from drivers side and see if you feel wet or see antifreeze. Sounds as if core is bad. Check in forum for how to replace, was just posted in Cooper S and does not sound hard. I guess all of our 03s might be due.

 

I have recently experienced the same problem with mine. I normally have my heat set to either 70 or 72. On my way home from work on Friday, I noticed it was only blowing cool air and the temp gauge was in the middle. I tried turning up the heat to 76 and turning the fan up. Once I did that, the temp gauge shot up very quickly. I noticed this and immediately turned off the "heat". Once I did that, the temp gauge returned to normal.

When I got home, I checked the antifreeze tank. It was dry so I filled it up to the max line and ran the car for about 5 mins. I checked the tank and it was still showing at max and there was something dripping on to the ground. I did not have the heat on when I ran the car. I dabbed a bit of the liquid with my finger and noticed it had a reddish tint to it...the antifreeze I put in the car is green. I tasted a bit and it was tangy...that's antifreeze alright.

This morning I dropped it off at the garage...20 degrees out and still no heat. I'm pretty sure there's an antifreeze leak somewhere, I'm just hoping it's a hose and not the water pump.

Anyone else have this problem? Any ideas what could be the issue? Thanks in advance.